Is Earth the Universe's only inhabited planet - if not, have aliens already made contact: this book examines the evidence..... Scientists have been searching outer space for signs of alien intelligence for decades, as yet with no confirmation that life exists anywhere beyond earths atmosphere. Yet it seems inconceivable that ours is the only intelligent life in an infinite universe over an infinite time. It may be that we simply have not managed to locate the evidence that would prove there is life out there - or that we are looking for the wrong kind of signals. And there are those who believe that alien encounters are a daily occurence here on earth. There is evidence to support both viewpoints in Alien encounter.